Rotary pump with intermeshing helical ribs

ABSTRACT

A rotary pump for liquids comprising a double cylinder housing of symmetrical form containing a driving and a driven rotor carrying two pairs of intermeshing helical ribs, and a pair of intermeshing gears, a covered plate on one end of the housing for supporting a thrust bearing for the driving rotor and a journal bearing for the driven rotor, a plate on the other end of the housing for supporting a journal bearing for each rotor, and a gear housing on the latter plate to form a lubricant chamber for the intermeshing gears.

United States Patent Albert A. Zalis Warren, Mass. App]. No. 799,200

Filed Feb. 14, 1969 Patented June 29, 1971 Assignee Warren Pumps, Inc.

Warren, Mas.

Inventor ROTARY PUMP WITH INTERMESIIING HELICAL RIBS 2 Claims, 3 Drawing Figs. U.S. Cl 418/202 Int. Cl F0lc 1/16 Field of Search 103/127, 128,126;230/143;123/l2;9l/84;418/202 References Cited UNITED STATES PATENTS 2/1929 Tifft 103/128 2,659,239 11/1953 Nilsson et a1.

2,693,762 11/1954 Sennet FOREIGN PATENTS 430,601 6/1935 Great Britain 448,235 6/1936 Great Britain...

648,055 12/1950 Great Britain 1,083,197 9/1967 Great Britain Primary Examiner Henry F. Raduazo Att0rney-Norman S. Blodgett ABSTRACT: A rotary pump for liquids comprising a double cylinder housing of symmetrical form containing a driving and a driven rotor carrying two pairs of intermeshing helical ribs, and a pair of intermeshing gears, a covered plate on one end of the housing for supporting a thrust bearing for the driving rotor and a journal bearing for the driven rotor, a plate on the other end of the housing for supporting a journal bearing for each rotor, and a gear housing on the latter plate to form a lubricant chamber for the intermeshing gears.

PATENIED JUH29 L9H SHEET 1 8F 2 FIG.2

INVENTOR. A. ZALIS BY m ATTORNEY ALBERT PATENTEUJUHZQIBTI 3,589,843

sum 2 or 2 FIG?) ROTARY PUMP WITH INTERMESI'IING HELICAL RIBS SUMMARY OF THE INVENTION The invention consists of a rotary pump for liquids and comprises two rotors carrying intermeshing helical gears. Pumps of this kind are known, but have not been designed for maximum efficiency, long life and dependability which requires a specific arrangement of housing parts and rotor bearings that is not found in previously produced pumps.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention, however, may be best understood by reference to one of its structural forms, as illustrated by the accompanying drawings, in which:

FIG. 1 is a horizontal longitudinal sectional view of the FIG. 2 is a partial vertical section thereof, and

FIG. 3 is an enlarged view of a portion of the pump.

DESCRIPTION OF THE PREFERRED EMBODIMENT The pump comprises a double cylinder housing 1 of symmetrical form. The housing 1 contains a driving rotor 2 and a driven rotor 3, the two rotors carrying two pairs of intermeshing helical ribs and can be rotated in either direction so as to drive the material toward the central chamber 4 which is in communication with an outlet port 6-at the middle of the housing 1. The outer ends of the rotors are connected by suitable passages through the housing to an inlet port 20.

The driving rotor 2 carries an extension 19 to be driven by any suitable source of power and is kept in correct position longitudinally by a thrust bearing 7 at its opposite end, while near its inner end it is given the necessary lateral support by a journal bearing 8, as well as a journal bearing 9 spaced axially therefrom.

The driven rotor is supported only by journal bearings and without any thrust bearings, as by journal bearings 10, 11, and 12.

The bearings 9 and 12 are supported by a plate 13 secured to one end of the housing, while the bearings 8 and 11 are supported by a similar plate 14 secured to the other end of the housing. A cover member 15 is mounted on the plate 13 to keep the bearings 9 and 12 supplied with lubricant, while a somewhat larger cover member 16 is mounted on the plate 14, not only to keep the bearings 7, 8, 10, and 11 supplied with lubricant, but also to house the intermeshing gears 17 and 18 on the rotors 2 and 3, respectively, which are needed in pumps of this kind to keep the two rotors in synchronism with each other.

Bellows-type mechanical seals 21 and 22 are provided on the shafts adjacent the end bearings. These seals are formed with both faces of solid tungsten carbide. The seals are located in the fluid being pumped so that external lubrication oil and centrifugal force will keep the faces clean. They are designed so that field installation is extremely easy. It should be noticed that, contrary to usual practice, the rotors 2 and 3 are integral; that is to say, in the past, the screws have been formed on sleeves which, in turn, have been fitted over shafts; In this case, because of the peculiarities of this design, as will be further explained, the screws and shafts are integrally formed. It should be noted that portions 23 and 24 of maximum diameter lie in the central chamber 4 where the maximum load is experienced. The timing gears 17 and 18 are made of steel which has been carbonized and hardened. The cover member 16, which envelopes the timing gears 17 and 18, is suitably jacketed, in order to cool the lubricating oil. Cooling is accomplished by circulating fluid through this jacket. The cover is made of lightweight material, such as aluminum, in the larger sizes to permit easy field handling without cranes when maintenance is necessary. Even though the bearings are externally lubricated by an oil bath, the distance between the bearings in this particular design is less than the normal screw pump designs, which means that there is reduced deflection under load.

As is best evident in FIG. 3, the end plates 14 and 13 are accurately positioned and located by means of large, straight, hardened-and-ground dowels 32. This permits the screw rotors 2 and 3 to be located eccentrically of their bores and in the bottom portion thereof in the preferred embodiment. The use of the hardened and ground dowels means that future maintenance work is greatly simplified, and that the plates will not have to be removed for the replacement of mechanical seals. In any case, the location of the rotors within their bores is very important because the deflection is in the upward direction and, by accurately and eccentrically placing the rotors in their bores, it is possible to prevent them from rubbing against the bores on the other side whenunder pressure.

It should be noted that the heavy duty roller bearings are mounted in special cartridges 30 for ease of replacement and for easy inspection of mechanical seals. These roller bearings are of the separable inner-race type, so that the bearing cartridge with the rollers and the outer race can be easily removed. The shaft is so dimensioned as to prevent interference in this area. Large oil level indicators 31 eliminate turbulence and easily show existing level. Their external design prevents breakage, which is so common with separately mounted oil level indicators.

It can be seen from a study of the present invention that the inventor has conceived a high-pressure screw pump in which the bearings and timing gears are placed and positioned externally of the chamber containing the fluid being pumped. This is especially important in the case of the pumping of chemically active or mechanically abrasive fluids. By making the rotors in integral form with the large-diameter portions 23 and 24 at the point where the greatest load (and, therefore, the greatest deflection) takes place, it is possible to maintain the deflection at a minimum for a given pump output pressure.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. It is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.

The invention having been thus described, what I claim as new and desired to secure by Letters Patent is:

l. A rotary pump comprising a double bored housing with a central high-pressure discharge port containing a driving and a driven rotor, each rotor having two sets of intermeshing helical ribs which are of opposite hand separated in the middle of the rotor adjacent the said discharge port, and each rotor also having intermeshing gears to keep the two rotors in synchronism with each other, each rotor being located eccentrically of its bore with the eccentricity in the direction away from the high-pressure discharge port, a cover plate on one end of the housing for supporting bearings for the driving rotor and the driven rotor, a plate on the other end of the housing for supporting a bearing for each rotor, and intermeshing gears on the two rotors to keep them in synchronism with each other, each rotor being integrally formed with a large diameter portion located between the helical ribs, and a plurality of accurately machined dowel-and-socket arrangements extending between said housing and said plates.

2. A rotary pump comprising a double bored housing with a central high-pressure discharge port containing a driving and a driven rotor, each having two sets of intermeshing helical ribs which are of opposite hand separated in the middle of the rotor adjacent the said discharge port, andmeans comprising intermeshing gears to keep the two rotors in synchronism with each other, a cover and plate on one end of the housing supporting bearings for the driving rotor and the driven rotor, a second plate on the other end of the housing supporting a bearing for each rotor, a cover member on the second plate to keep the intermeshing gears supplied with lubricant, each rotor being integrally formed with a large diameter portion located between the helical ribs for resistance against deflecseals located between the rotor portions in the housing containing the fluid to be pumped and the bearing plates. 

1. A rotary pump comprising a double bored housing with a central high-pressure discharge port containing a driving and a driven rotor, each rotor having two sets of intermeshing helical ribs which are of opposite hand separated in the middle of the rotor adjacent the said discharge port, and each rotor also having intermeshing gears to keep the two rotors in synchronism with each other, each rotor being located eccentrically of its bore with the eccentricity in the direction away from the highpressure discharge port, a cover plate on one end of the housing for supporting bearings for the driving rotor and the driven rotor, a platE on the other end of the housing for supporting a bearing for each rotor, and intermeshing gears on the two rotors to keep them in synchronism with each other, each rotor being integrally formed with a large diameter portion located between the helical ribs, and a plurality of accurately machined doweland-socket arrangements extending between said housing and said plates.
 2. A rotary pump comprising a double bored housing with a central high-pressure discharge port containing a driving and a driven rotor, each having two sets of intermeshing helical ribs which are of opposite hand separated in the middle of the rotor adjacent the said discharge port, and means comprising intermeshing gears to keep the two rotors in synchronism with each other, a cover and plate on one end of the housing supporting bearings for the driving rotor and the driven rotor, a second plate on the other end of the housing supporting a bearing for each rotor, a cover member on the second plate to keep the intermeshing gears supplied with lubricant, each rotor being integrally formed with a large diameter portion located between the helical ribs for resistance against deflection of the rotor at its central portion, the plates being accurately located on the housing for the location of the axis of the rotors spaced from and parallel to the axes of the bores, and seals located between the rotor portions in the housing containing the fluid to be pumped and the bearing plates. 